Typically, a regular LC lens is polarization-dependent. In order to obtain a polarization-independent LC lens system, two or more LC lenses or sub-lenses are stacked together and mutual orthogonal orientation is attempted. Each sub-lens is manufactured separately and special precise mechanics are required in order to achieve a mutual alignment of the optical axes. This constitutes a complicated and challenging process. A poor alignment generally induces polarization aberration which affects the quality of image, i.e., image doubling.
An attempted solution to this problem known in the art is the use of alignment layers. More specifically, the alignment material which typically comprises a photo-aligned polymer is staked in layers on a substrate. The alignment material is capable of generating pretilt angles (Chung-Yung Lee et al., 2009).
Another attempted solution constitutes of using a single polarization-dependent LC lens, snap shooting of two frames with computer processing (Bao R. et al., 2014). However, with this approach the exposure time is doubled, which decreases the probability of taking a sharp picture due to shake-vibration and scene change possibility.
There is a need for more efficient polarization-independent LC lenses and LC lens systems. Also, there is a need for improved and efficient methods for obtaining such LC lenses and LC lens systems.